Method for vacuum treatment of workpieces and vacuum treatment installation

ABSTRACT

A method for manufacturing workpieces treated in a vacuum includes providing first and second vacuum chambers having first and second vacuum pumps, respectively. A vacuum is generated in the first and second vacuum chambers using the second vacuum pump. The second vacuum pump is connected by valves between the first vacuum chamber through the first vacuum pump and the second vacuum chamber. The valves are operated to evacuate the second vacuum chamber, followed by processing the workpieces in the first vacuum chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a divisional application of U.S. patentapplication Ser. No. 09/958,404, filed Jan. 22, 2002, the entirety ofwhich is hereby incorporated by reference.

FIELD AND BACKGROUND OF THE INVENTION

[0002] Method for vacuum treatment of workpieces and vacuum treatmentinstallation. The present invention relates to a method for the vacuumtreatment of workpieces, in which a workpiece is introduced into aninterlock chamber open to the ambient atmosphere, the interlock chamberis pumped out after it had been closed off from said ambient atmosphere,the interlock chamber is opened into an at least partially pumped-offvacuum chamber configuration, the workpiece subsequently is transportedfrom the interlock chamber into the configuration and treated in theconfiguration, the workpiece subsequently is transported back from theconfiguration into the interlock chamber, the interlock chamber isclosed against the configuration, is subsequently flooded and, lastly,the treated workpiece is carried from the flooded interlock chamber intothe ambient atmosphere, wherein at least a portion of the configurationis pumped out by means of a turbo vacuum pump with a forevacuum pumpoperationally connected therewith at the high-pressure side and theinterlock chamber is pumped out by means of an interlock pump.

[0003] The present invention relates further to a vacuum treatmentinstallation comprising an interlock chamber, an interlock pumpconnected therewith, further communicating with the interlock chamber avacuum chamber configuration operationally connected with at least oneturbo vacuum pump, with which latter is associated at the high-pressureside a forevacuum pump.

[0004] In FIG. 1 is depicted in the form of a function block diagram onesuch prior known configuration, in which said prior known workpiecetreatment method is readily evident to a person skilled in the art.

[0005] According to FIG. 1, an interlock chamber 1 with lock valve 3against ambient atmosphere U is provided with a lock valve 5 against avacuum chamber configuration 7. The vacuum chamber configuration 7 cantherein comprise as a minimum configuration a single treatment chamber Bor one or several transport chamber(s) operationally connected with thelatter, again, one or several treatment chamber(s) B as well as, ifappropriate further interlock chambers depending on how complex thetreatment to be carried out on the workpieces is and how many steps itcomprises. As is readily familiar to a person skilled in the art, theworkpieces are introduced into the interlock chamber 1 with the lockvalve 5 closed and lock valve 3 is opened, whereupon the lock valve 3 isclosed and the interlock chamber 1 is evacuated by means of an interlockpump 9, such as for example a single- or multistage rotary vane pump andvia a valve 11.

[0006] In principle, on the vacuum chamber configuration 7 at least oneturbo vacuum pump 13 is provided, which pumps out at least the onetreatment chamber, if appropriate jointly in combination with atransport chamber associated with this treatment chamber. If severaltreatment chambers are provided which are to be pumped independently ofone another, it is entirely possible to provide several turbo vacuumpumps 13.

[0007] The at least one turbo vacuum pump 13, operationally connectedwith the vacuum chamber configuration 7, is succeeded at thehigh-pressure side by a forevacuum pump 15, in order to generate therequired forepressure at the turbo vacuum pump 13.

SUMMARY OF THE INVENTION

[0008] It is the task of the present invention to further develop themethod of the above described type such that it becomes cost-effectiveand that it becomes less susceptible to fault, further to simplify theinstallation of said type accordingly, and to realize it such that itrequires less maintenance and has greater compactness. This is achievedwith the method of said type thereby that as the forevacuum pump theinterlock pump is operationally connected with the turbo vacuum pump.

[0009] To solve said task the vacuum treatment installation of the abovedescribed type is distinguished thereby that the forevacuum pump,associated with the turbo vacuum pump, is the interlock pump. The methodaccording to the invention as well as also the configuration accordingto the invention are in particular well suitable for the treatment, inparticular coating, of disk-shaped workpieces, in particular of storagedisks, therein especially of optical data storage disks.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The invention will subsequently be explained in conjunction withthe drawing figures, in which:

[0011]FIG. 1 is a function block diagram of a prior art method;

[0012]FIG. 2 building on a representation according to FIG. 1, thefundamental further development according to the invention of the vacuuminstallation for realizing the production method according to theinvention; and

[0013]FIG. 3 schematically the realization of a highly compact vacuumtreatment installation according to the invention in a preferredembodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Using the same reference symbols, in FIG. 2 the same vacuumtreatment installation as depicted in FIG. 1, however, as will bedescribed in the following, is further developed according to theinvention.

[0015] According to FIG. 2 the forevacuum pump succeeding the turbovacuum pump 13 at the high-pressure side is omitted. In its place theinterlock pump 9 is also employed as the forepump of the turbo vacuumpump 13. Therefore, in FIG. 2 the interlock-/forevacuum pump used incombination is denoted by the combined reference symbol 9/15. In termsof signal technology thus the low-pressure side of theinterlock-/forevacuum pump 9/15 is operationally connected via acontrolled switch-over device 17 with the interlock chamber as well asalso with the high-pressure side of the turbo vacuum pump 13. Whenloading a workpiece into the interlock chamber 1, for pumping out theinterlock chamber 1 the low-pressure input of the interlock-/forevacuumpump 9/15 is isolated via the switch-over unit 17 from the high-pressureport of the turbo vacuum pump 13 and operationally connected with theinterlock. After pumping out the interlock chamber 1 to transferpressure to the vacuum chamber configuration 7, the low-pressure inputof the interlock-/forevacuum pump 9/15 is operationally connected viasaid switch-over device 17 with the high-pressure side of the turbovacuum pump 13.

[0016] It is entirely possible to realize the switch-over configuration17, as indicated in dashed lines at 17 a and 17 b, by means of valvescontrollable independently of one another, or by means of a two-wayvalve such as the device 17 is also depicted.

[0017] The control of said operational connections can therein takeplace under pressure control, for example by measuring the pressure inthe interlock chamber 1 and switching-over to forepump operation of theinterlock-/forevacuum pump 9/15 upon reaching a predetermined pressurevalue or it can take place at a predetermined periodicity according topre-ascertained cycles.

[0018] Preferably a turbo vacuum pump 13 is employed which at thehigh-pressure side can work against a maximally high pressure,preferably of at least 1 mbar, in particular preferred of at least 10mbar.

[0019] For this purpose are especially suitable turbo drag pumps orturbo pumps combined with Holweck stages at the pump output. As theinterlock- 1 forevacuum pump, furthermore, a single- or multistagerotary vane pump is preferably used.

[0020] When applying said preferably used turbo vacuum pump 13 this evenpermits using a very “clean” membrane pump as the interlock-/forevacuumpump.

[0021] Furthermore, the interlock chamber 1 should be pumped out asrapidly as possible such that at the high-pressure side the turbo vacuumpump 13 does not need to operate too long in the operational connection,which in this case is closed, to the switch-over configuration 17 or toa closed valve 17 a. Accordingly is dimensioned, on the one hand, thecapacity of the provided interlock-/forevacuum pump 9/15, but inparticular the volume of the interlock chamber 1. The latter should beselected to be of minimum size, the ratio of the interlock chambervolume to the volume pumped out by the provided turbo vacuum pump 13should be selected to be maximally 1:40, preferably even maximally1:100.

[0022] In FIG. 3 is depicted schematically a preferred, highly compactvacuum treatment installation according to the invention for the vacuumtreatment according to the invention of workpieces, in particularcircular disk-shaped workpieces, such as for example, and preferably, ofdata storage disks.

[0023] In a housing 7 a of the vacuum chamber configuration 7 atransport device 21 is provided driven rotationally movable about anaxis A by means of a drive 20, with transport arms 23 bent off at anangle with respect to the axis of rotation A. By means of associatedlinear drives, such as shown at 25, the transport arms 23 areencapsulated, extendable and retractable, as shown by F. At their endsthey support workpiece carrier plates 27 for (not shown) workpiecedisks. The vacuum chamber configuration 7 comprises a working station29, for example flanged onto the housing 7 a, a working station 29, suchas for example a sputter station.

[0024] The volume of a provided interlock chamber 1 a is minimizedthereby that it is virtually integrated into the section thickness ofthe wall of the housing 7 a. This minimization, previously alreadydiscussed in conjunction with FIG. 2, of the interlock chamber volume ispossible in the extent depicted in FIG. 3, in particular in combinationwith the treatment, for example in particular of the coating, ofdisk-shaped workpieces, in particular of storage disks, thereinespecially of optical data storage disks.

[0025] With the depicted installation according to the invention inparticular according to FIG. 3, cycle times, for example, of less than 2seconds were attained in the CD production or the production of opticalstorage disks, concretely of 1.8 seconds at a lock passing time of 0.4seconds.

[0026] Fundamentally it is preferably proposed that the sub-intervalrange of the cycle time “transportation and treatment” is at least 50%of the total cycle time, preferably at least 60%, or expressed withrespect to the “lock passage time”, at least 300%.

[0027] The outer lock valve is denoted by 3 a, the inner one is formedby the workpiece carrier plate 27 on the particular transport arm 23. Byrotation of the transport device 21 about axis A, the provided transportarms or the retracted carrier plates 27 are first placed into positiononto interlock chamber 1 a and working station 29. By extending the armsthe corresponding stations 1 a, 29 are sealed off, either by setting upa pressure stage, such as by means of labyrinth sealing, orvacuum-tight, for example form-fittingly. On the one hand, in this caseat the interlock chamber 1 a by opening the lock valve 3 a a workpieceis input or output, while simultaneously at the working station 29,either closed or sealed according to the requirements, the workpieceworking takes place.

[0028] A configuration of this type is fully described in EP A 0 518 109corresponding to U.S. Pat. No. 5,245,736 by the applicant as well as inthe present application. As is evident, the switch-over device 17,described in conjunction with FIG. 2, is preferably realized by means ofvalves 17 b′ or 17 a′ inserted into the connection line. In theembodiment depicted, the turbo vacuum pump 13 pumps out the interiorvolume of the transport chamber as well as also the process chamber. Aratio of the volumes of interlock chamber 1 a to the volume pumped outby the turbo vacuum pump 13 of 1:110 was realized.

[0029] In FIG. 3, 31 denotes a flooding valve for the interlock chamber1 a, 33 the flooding valve, already depicted in FIGS. 1 and 2, for theturbo vacuum pump 13.

What is claimed is:
 1. A method for manufacturing workpieces treated invacuum comprising: providing a first vacuum chamber connected with afirst vacuum pump; providing a second vacuum chamber; providing a secondvacuum pump dischargeable into atmosphere for producing a vacuum in boththe first and second vacuum chambers; providing a first valve forconnecting said second vacuum pump with the first vacuum chamber via thefirst vacuum pump; providing a second valve for connecting the secondvacuum pump with the second vacuum chamber; closing the first valve andopening the second valve for evacuating the second vacuum chamber; andprocessing a workpiece in the first vacuum chamber.
 2. The method ofclaim 1, further comprising the step of closing the second valve afterevacuation of the second vacuum chamber and opening the first valve forevacuation of the said first vacuum chamber.
 3. The method of claim 1,wherein said first pump is a turbo-vacuum pump.
 4. The method of claim1, wherein said second pump is a single or multistage rotary valve ormembrane pump.
 5. The method of claim 1, wherein said vacuum treatedworkpiece is a disc-shaped workpiece.
 6. The method of claim 1, whereinsaid vacuum treated workpiece is an optical storage disc, said treatmentcomprising coating.
 7. The method of claim 1, further comprising thestep of introducing at least one of said workpiece in one of said firstand second vacuum chambers and removing said workpiece from one of saidfirst and second vacuum chambers after said treating, the time-spanbetween said introducing and said removing being no more than 2 seconds.8. A method for manufacturing a workpiece treated in vacuum comprising:providing a first vacuum chamber connected with a first vacuum pump;providing a second vacuum chamber; transporting a workpiece to the firstchamber; providing a second vacuum pump dischargeable into atmospherefor producing a vacuum in both the first and second vacuum chambers;providing a first valve for connecting said second vacuum pump with thefirst vacuum chamber via the first vacuum pump; providing a second valvefor connecting the second vacuum pump with the second vacuum chamber;closing the first valve and opening the second valve for evacuating thesecond vacuum chamber; and treating the workpiece in the first vacuumchamber.
 9. The method of claim 8, wherein the workpiece is adisc-shaped workpiece, the method including providing the second chamberto be an interlock chamber and providing a lock valve between the firstand second chambers for connecting the chambers to each other and forpassage of the workpiece between the chambers, the workpiece beingtransported from the second chamber to the first chamber before thetreating step.
 10. The method of claim 9, including closing the secondvalve and opening the first value for evacuating the first chamber, atotal time for transporting and treating the workpiece being at least50% of a total cycle time for evacuating the first and second chambersplus the time for transporting and treating the workpiece.
 11. Themethod of claim 8, including closing the second valve and opening thefirst value for evacuating the first chamber, a total time fortransporting and treating the workpiece being at least 50% of a totalcycle time for evacuating the first and second chambers plus the timefor transporting and treating the workpiece.
 12. A method formanufacturing a workpiece treated in vacuum comprising: providing afirst vacuum chamber connected with a first vacuum pump; providing asecond vacuum chamber; providing a second vacuum pump dischargeable intoatmosphere for producing a vacuum in both the first and second vacuumchambers; providing a switch-over unit having a first position forconnecting said second vacuum pump with the first vacuum chamber via thefirst vacuum pump, and a second position for connecting the secondvacuum pump with the second vacuum chamber; moving the switch-over unitto the first position for evacuating the first vacuum chamber; movingthe switch-over unit to the second position for evacuating the secondvacuum chamber; and processing a workpiece in the first vacuum chamber.13. The method of claim 12, wherein the workpiece is a disc-shapedworkpiece, the method including providing the second chamber to be aninterlock chamber and providing a lock valve between the first andsecond chambers for connecting the chambers to each other and forpassage of the workpiece between the chambers, the method includingtransported the workpiece from the second chamber to the first chamberbefore the treating step.
 14. The method of claim 13, wherein a totaltime for transporting and treating the workpiece is at least 50% of atotal cycle time for evacuating the first and second chambers plus atime for transporting and treating the workpiece.
 15. The method ofclaim 12, wherein a total time for transporting and treating theworkpiece is at least 50% of a total cycle time for evacuating the firstand second chambers plus a time for transporting and treating theworkpiece.